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F-35 Program InformationNon Export Controlled Information – Releasable to Foreign Persons

Integration of Ground and Flight Testing on F-35 Lightning II Program

04 December 2007J. B. Yates

Lockheed Martin Aeronautics

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F-35 Program InformationNon Export Controlled Information – Releasable to Foreign Persons

Acknowledgements

• Robert J. Burt, F-35 Chief Structures Engineer• Phil Gross, F-35 Deputy Chief Structures Engineer• Pablo Guerrero, F-35 Structural Test Planning• Marguerite Christian, F-35 Static Test Technical Lead

– John Bradley, CTOL– Todd Bevan, CV – Jim Doyle, STOVL– Don Whiteley, STOVL

• Steve Owens, F-35 Structural Certification

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F-35 Program InformationNon Export Controlled Information – Releasable to Foreign Persons

F-35 Program Overview

• Family of Three Air Vehicle Variants, with Similar Structural Arrangements– Each Variant is Designed To Satisfy the Requirements of a

Separate Military Branch – F-35A = Conventional Take-Off and Landing (CTOL) Variant – F-35B = Short Take-off and Vertical Landing (STOVL) Variant – F-35C = Carrier Variant (CV)

• Simultaneous Development and Testing the Three F-35 Variants Provides Both Opportunities and Challenges– Opportunities – Commonality & Efficiencies– Challenges – Resource & Schedule Concurrency

4Use or disclosure of the information contained herein is subject to the restrictions on the Cover Page

LM JSF Team Program Information

LM JSF Team Program InformationNon-Technical Data – Releasable to Foreign Nationals

F-35 Variant Planform Comparison

STOVL

Span (ft) 35Length (ft) 51.2Wing Area (ft2) 460

240A-4.4

CTOL

Span (ft) 35Length (ft) 51.4Wing Area (ft2) 460

Span (ft) 43Length (ft) 51.5Wing Area (ft2) 667

CV

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F-35 Structural Ground Test Program

• Full Scale Static & Durability Test of Each Variant– Six Full Scale Test Airframes– Four Commonly Designed Test Fixtures – CV Static Test Airframe Also Used as Drop Test/

Barricade/Live Fire Article• Proof Tests Conducted on Each Variant’s Loads

Instrumented Flight Test Aircraft– Provides Larger Initial Flight Envelope– Reduces Early Flight Test Dependency on Static Test

F-35 Structural Test Program Is A Key Element of a Rigorous and Disciplined Structural Integrity Program

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F-35 Full Scale TestsLocations & Fixture Sharing

LM Fort Worth, US BAES Brough, UK

STOVL Static STOVL Durability CTOL Static

CTOL Durability

CV Durability

CV Static

CV Drop

Vought, Grand Prairie TX, US

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Test Fixture Design Commonality Enabled by Structural Similarity

• Similarity of Airframe allows efficiencies in load arrangement design as well as load condition development– Common Fuselage Bulkhead Stations– Similar Wing & Tail Box Planforms (STOVL & CTOL)

View Looking Down on Upper Surface

1FZ01

1FY04

1FY031FY01

1CY01

1CY02

1LC071LC05

1LC031LC01

1WZ09

1WZ01

1WZ13

1WZ15

1WZ05

1WZ03

1WZ07

1WZ11

1WZ17

1TC01

1TC03

1TC05

1LC081LC06

1LC041LC02

1WZ10

1WZ02

1WZ14

1WZ16

1WZ06

1WZ04

1WZ08

1WZ12

1WZ18

1TC02

1TC04

1TC06

1AZ01

1VC12

1VC081VC18

1VC14 1VC161VC10

1VC06

1VC04

1VC02

1VC13

1VC15

1VC05

1SC07

1JC02

1JC03

1JC04

1JC01

1FZ01

1FY04

1FY031FY01

1CY01

1CY02

1LC071LC05

1LC031LC01

1WZ09

1WZ01

1WZ13

1WZ15

1WZ05

1WZ03

1WZ07

1WZ11

1WZ17

1TC01

1TC03

1TC05

1LC081LC06

1LC041LC02

1WZ10

1WZ02

1WZ14

1WZ16

1WZ06

1WZ04

1WZ08

1WZ12

1WZ18

1TC02

1TC04

1TC06

1AZ01

1VC12

1VC081VC18

1VC14 1VC161VC10

1VC06

1VC04

1VC02

1VC13

1VC15

1VC05

1SC071SC07

1JC02

1JC03

1JC04

1JC01

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F-35 Program InformationNon Export Controlled Information – Releasable to Foreign Persons

F-35 Load Case Selection Process

• Comprehensive Set of Load Conditions Selected For Strength Certification of Each Variant– Selected to Exercise All Major Components, Control Surfaces,

Weapons Hardpoints and Flight Opening Doors• Two Independent Processes Used To Determine Candidate Load Cases

For Static Testing– External Loads Process

• External Load Envelopes At Specified Section Cuts Used To Identify Critical Loading Conditions

• Provided Earlier Support for Test Fixture Design– Strength & Stability Margin Process

• Critical Margins And Failure Modes Reviewed to:– Confirm Selections from External Loads Process – Referee Between Similar Conditions

• Candidate Load Conditions from the Two Processes Consolidated ToDefine Final Load Cases Considering:– Structural Symmetry & Similarity– Load Case Similarity – Discrete Load Sources

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External Load Case Selection Process

• 15 Integrated Load Envelopes Used in Selection Process• Perimeter of the Load Envelopes Initially Selected to Provide Early

Guidance For Test Fixture and Load Actuator Design (Over 100 Cases)• Candidate List Selection Based on Knowledge of Primary Structural

Drivers and Symmetry – Reduced to 30 - 45 Conditions Depending on Variant – Load Arrangement Refined to Improve Match of Selected Conditions

Wing Root BM-TQ

-3,000,000

-2,000,000

-1,000,000

0

1,000,000

2,000,000

3,000,000

4,000,000

5,000,000

-2,000,000 -1,500,000 -1,000,000 -500,000 0 500,000 1,000,000 1,500,000 2,000,000 2,500,000 3,000,000

TQ

BM

Test Loads

Parent Loads

BTP Envelope

VT Root BM-TQ

-1,000,000

-800,000

-600,000

-400,000

-200,000

0

200,000

400,000

600,000

800,000

1,000,000

-800,000 -600,000 -400,000 -200,000 0 200,000 400,000 600,000 800,000

TQ

BM

Test Loads

Parent Loads

BTP Envelope

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External Load Section Cut Locations

VT Mid Span

VT Root

Wing Tip

Wing Mid

Wing Root

Fwd FuseCtr Fuse Aft Fuse

HT Bending Moment

HT Hinge Moment

Control Surface Hinge Moments For LEF, TEF & Rudder Also Used

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Strength & Stability Margin Based Selection

• Each Structural Analysis Team Reviewed Their Stress Analysis for Critical Loadings

– Emphasis on Stability Related Margins– Preference to Conditions Which Drive Large Areas of Structure– Considered Only Loads Which Can Be Represented on Full Scale Static Test

• Review of Critical Margins Confirms Adequacy of Envelopes Chosen for External Loads Review

– Used to Referee Between Similar Cases Near Envelope Perimeter– Ensures All Critical External Load Drivers Have Been Addressed

• Prompted the Evaluation of LHS and RHS Boom External Load Envelopes

TestDesign

Wing Box Upper Skin – Min Principal Running LoadInternal Loads Envelope Comparison

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F-35 Program InformationNon Export Controlled Information – Releasable to Foreign Persons

CTOL Global Test Load Conditions

Mach Alt Nz Maneuver & Description

Win

g R

oot

Win

g M

idsp

an

LEF

TEF

FF CF

AF

VB

M/L

BM

AF

VB

M/T

Boo

ms

LH B

oom

RH

Boo

m

HT

VT

Roo

t

VT

Mid

span

Rud

der

1 Med SL Min RT - R Symmetric Pull-Up/Push-Over X X X2 Med SL Max RT - R Symmetric Pull-Up/Push-Over X X X X X X X X3 Med SL Max RT - R Symmetric Pull-Up/Push-Over X4 Med SL Min RT - R Symmetric Pull-Up/Push-Over X X X X5 Med SL Man RR - R 360 deg Roll, Full Rate X X X6 Med SL Man PL - L Roll Pull-Out, Full Rate X X X7 Low SL Max A3 - Abrupt Pull-Up/Push-Over Type 3 X X X X8 Med SL Max RW - R Trim Open-Close Weapon Bay Doors X9 Med SL Man 0L - L Yaw Gust X X X X10 High Alt Man RR - R 360 deg Roll, Full Rate X11 Med SL Man RL - L 360 deg Roll, Full Rate X X12 Low Alt Man RR - R 360 deg Roll, Full Rate X X X X X13 Med SL Max RT - R Symmetric Pull-Up/Push-Over X X14 High Alt Man RT - R Symmetric Pull-Up/Push-Over X X X15 Med SL Min RW - R Trim Open-Close Weapon Bay Doors X X X16 High Alt Man QL - L 180 deg Roll, Full Rate X X17 Low SL Max RT - R Symmetric Pull-Up/Push-Over X X X X X X18 Med SL Max A1 - Abrupt Pull-Up/Push-Over Type 1 X X X19 Med SL Max HS - Hammer Shock X20 Med SL Man PR - R Roll Pull-Out, Full Rate X X21 Med SL Man QR - R 180 deg Roll, Full Rate X22 Med Alt Man RL - L 360 deg Roll, Full Rate X X X X23 Med Alt Man RR - R 360 deg Roll, Full Rate X X X X24 Med SL Man RR - R 360 deg Roll, Full Rate X25 Med SL Man QL - L 180 deg Roll, Full Rate X26 Med Alt Man RL - L 360 deg Roll, Full Rate X X X27 High Alt Man QL - L 180 deg Roll, Full Rate X X X X28 Med SL Man SR-R Sideslip X X

Wing Fuselage Tail

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STOVL Local Static Tests

3 BSN Doors

Refuel Probe Back-up Structure and Mechanism

Outboard WBDInboard WBD and Cradle

Fwd MLG DoorMLG Inboard Trunnion Support Structure

MLG Drag Brace Interface at FS450MLG Outboard Trunnion Support Structure

NLG Doors

Fwd Fuse Side SkinOutboard Store Sta 4/8

Jacking

Hoist

Cockpit Pressure

Fuel Tank PressureEngine Thrust Mount

Engine Mount-Fwd Upper

Vane Box

Lift Fan Exhaust

Lift Fan Mounts

Boarding Ladder Door

Aux Air Inlet

Lift Fan Inlet

RCN Door Attach Structure

Nose Landing Gear Backup Structure

Wing-Pylon Sta 9Wing-Pylon Sta 10Wing-Pylon Sta 11

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Structural Similarity Enables Cross-Variant Verification Testing

• CV & CTOL– Weapons Bay Doors, RGA, & Backup Structure– Canopy

• STOVL & CTOL– Main & Nose Landing Gear Doors – Gear Door Uplocks

• STOVL & CV– Air Refuel Probe

• Tri-Variant– Engine Mounts– Wing Pylons & Hardpoints

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Results of Load Case Selection

473428Total Full

Airframe Cases

* CV Load Case Selections are Still Preliminary

255134Local Tests

8106Tail Group

15109Wing Group

241413Fuselage Group

CV*STOVLCTOL

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Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 QQ2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q

Flight TestMilestones

Full Scale TestMilestones

BG-1 Static Test

BF-1 Flying Qualities

BF-2 Flutter & Flying Qualities

BF-3 Loads

Phase 0 – Cockpit & Fuel Tank Pressure & Vane BoxPhase 1 – CPO & AAIPhase 2 – NLG, LFI, LFE DoorsPhase 3 – Refuel Probe & Weapons Bay DoorsPhase 4 – 115% & 150% DLL Full Airframe Maneuver & 3BSM ConditionsPhase 5 – MLG & RCN Door Local ConditionsPhase 6 – Tow, Taxi, MLG, Store Hard Point, & Boarding Ladder; Local ConditionsPhase 7 – Engine and LF Mounts, Tie Down, Jacking & Hoisting; Local Conditions

Cal/Proof Test

AF-2AF-2 CF-2CF-2

Cal/Proof TestHover Pit Testing

BF-3BF-3

ReportComplete

BF-1 Cabin & Tank Pressure Proof Test

AF-1AF-1

BG-1 in support of flight testBG-1 in support of flight test

Calibration Test

Flight TestingFlight Testing

FF

Ground Field OpsGround Field Ops

Component Static TestsComponent Static TestsFSST PhasesFSST PhasesLive Fire TestLive Fire Test

Test ArticlePrep & SetupTest ArticlePrep & Setup

Monitored A/C 80% ALE

Un-Monitored A/C 64% ALE

AirworthinessAirworthinessFerryFerryOther as LabeledOther as Labeled

Initial STOVL Transitions

Flutter Loading 1

Loads - A/C 80%DLL Loads - A/C 100%DLL

Un-Monitored A/C 80% ALE

Monitored A/C 100% ALE

Weapons TestingWeapons Testing

FF

FF

F-35 Schedule Integration• An Integrated Flight & Ground Test Program Has Been

Developed– Key Flight Envelope Expansion Milestones Defined– Test Conditions Sequenced to Support Progressive Flight

Clearance Build Up– Proof Testing Incorporated to Provide Early Flight Envelope

to 80% DLL for Loads Monitored AircraftSTOVL Ground and Flight Test Schedules

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Expanded View of STOVL Schedule

Q3 Q4 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q1Q3 Q4 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q1

BG-1 Static Test

BF-1 Flying Qualities

BF-2 Flutter & Flying Qualities

BF-3 Loads

Phase 0 – Cockpit & Fuel Tank Pressure & Vane BoxPhase 1 – CPO & AAIPhase 2 – NLG, LFI, LFE DoorsPhase 3 – Refuel Probe & Weapons Bay DoorsPhase 4 – 115% & 150% DLL Full Airframe Maneuver & 3BSM ConditionsPhase 5 – MLG & RCN Door Local ConditionsPhase 6 – Tow, Taxi, MLG, Store Hard Point, & Boarding Ladder; Local ConditionsPhase 7 – Engine and LF Mounts, Tie Down, Jacking & Hoisting; Local Conditions

Cal/Proof Test

AF-2AF-2 CF-2CF-2

Cal/Proof TestHover Pit Testing

BF-3BF-3

ReportComplete

BF-1 Cabin & Tank Pressure Proof Test

AF-1AF-1 Calibration Test

FF

Monitored A/C 80% ALE

Un-Monitored A/C 64% ALE

Initial STOVL Transitions

Flutter Loading 1

Loads - A/C 80%DLL Loads - A/C 100%DLL

Un-Monitored A/C 80% ALE

Monitored A/C 100% ALE

FF

FF

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Expanded View of CTOL Schedule

Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 QQ1Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 QQ1

AG-1 Static Test

AF-1 Flutter& Flying Qualities

AF-2 Loads

AF-3 MissionsSystems

Phase 0 – Cockpit & Fuel Tank PressurePhase 1 – CPO & IFRR Backup StructurePhase 2 –Weapons Bay Sta. 4/8 & 5/7 Store Hard PointsPhase 3 – 115% & 150% DLL Full Airframe ManeuverPhase 4 – Arrestor Gear & MLG Backup Structure & Uplocks,

Sta. 10/11 Store Hard Points, Taxi, & Tow: Local Cond. Phase 5 – Engine Mounts, Jacking, & Hoisting: Local Conditions

ReportComplete

Cal/Proof Test

A/C DeliveredTo Lab

AF-2AF-2

CF-2CF-2

Cal/Proof Test

BF-3BF-3 AF-1AF-1

FF

AF-1 Cabin & Tank Pressure Proof Test

Calibration Test

Monitored A/C 80% ALE

Un-Monitored A/C 64% ALE

Un-Monitored A/C 80% ALE

Monitored A/C 100% ALE

Loads - A/C 80%DLL Loads - A/C 100%DLLFF

FF

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Expanded View of CV Schedule

Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4Q1

CG-1 Drop/Static/Barricade/Live Fire Test

CF-1 Flutter &Flying Qualities

CF-2 Loads

CF-3 Ship Suitability

FF

A/C DeliveredTo Lab

Cal/Proof Test

AF-2AF-2

CF-2CF-2

Cal/Proof Test

BF-3BF-3 AF-1AF-1

CF-3 Cabin & Tank Pressure Proof Test

CF-1, CF-2 Cabin & Tank Pressure Proof Test

Calibration Test

Sea Trials - Initial (includes ferry to/from ship) w/C3

Roll-In Mk-7/E-28/JBO at LKEShip Suitability-Wave-Off & Bolter Performance & Deck Handling

Monitored A/C 80% ALE

Un-Monitored A/C 64% ALE

Un-Monitored A/C 80% ALE

Monitored A/C 100% ALE

FF

Static Test Report Complete

FF

Phase 5 –115% & 150% DLL Local Conditions------------ > Barricade Test------------ > Live Fire Test

------------ > Drop TestPhase 0 – Cockpit & Fuel Tank Pressure

Phase 2 – CPO & NLG DoorsPhase 3 – Strain Surveys & 6 Maneuver Conditions to 115% & 150% DLLPhase 4 – 115% & 150% DLL Maneuver Conditions

Phase 1 – Cats, Traps, MWB stores & LG BU Structure

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Summary

• F-35 Structural Test Program Benefits from Structural Similarity– Common Test Fixture Designs– Common Test Load Development Processes– Cross-Variant Verification Testing of Certain Structural

Components• Load Case Selection Process Ensures Static Test Adequacy

– Earlier Support for Development of Test Arrangement– Additional Confidence in Resulting Selections

• Structural Test Program Developed to Support Flight Test Requirements– Test Conditions Are Deliberately Sequenced to Provide

Timely Support for Key Flight Envelope Expansion Milestones

– Proof Tests of the Loads Instrumented Aircraft Incorporated to Provide Earlier Flight Envelope Expansion

F-35 Structural Ground Test Program Has Been Developed as Part of a Thorough and Disciplined Structural Integrity Program

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F-35 Program InformationNon Export Controlled Information – Releasable to Foreign Persons

Questions